1559T_Ch24_423-43810/20/054:54APa9e423 EQA 24 Carbohydrates:Polyfunctional Compounds in Nature ou'll begin to a of "real world"molecule es some spciastcrcochcnicaltcms.O can.then this chapter shoudotthe puze posd by some of the problem.If you to be good at deductive reasoning Outline of the Chapter 24-1,242,24-3 Names and Structures of Carbohydrates Be prepared for a lot of new terminology. 24-4 through 24-8 Polyfunctional Chemistry of Sugars The basics:mostly (but not entirely)review material 249,2410epbrseebniadDegrateionaf5ugors 24-11,24-12 Complex Sugars in Nature Keys to the Chapter The naming system pre organized into a semioffic amework that is universally used.S o.sugars are all ketones or alde ydes con Fischer projections.ith the carbon chain vertical and the carbony!gro nearest the top.If the stereocenter nearest thebottom of the Fischer projection has theHon th right,it has on,and th 24-l and242 On Is on the lent,you n. of one)of ny of thes the mirorm 423 24 Carbohydrates: Polyfunctional Compounds in Nature In this chapter you’ll begin to apply the material you’ve just seen to a major class of “real world” molecules, carbohydrates (sugars). For a change, nomenclature will play a more central role: The names of sugars and sugar derivatives follow their own independent system, which includes some special stereochemical terms. On the other hand, most of the reactions are old ones and are needed for only a limited number of purposes such as structure determination, interconversion of derivatives, and synthesis of one sugar from another. You need to be good at deductive reasoning so that you can solve the puzzles posed by some of the problems. If you can, then this chapter should not be too hard for you. Outline of the Chapter 24-1, 24-2, 24-3 Names and Structures of Carbohydrates Be prepared for a lot of new terminology. 24-4 through 24-8 Polyfunctional Chemistry of Sugars The basics: mostly (but not entirely) review material. 24-9, 24-10 Step-by-Step Buildup and Degradation of Sugars Application in synthesis and structure determination. 24-11, 24-12 Complex Sugars in Nature Keys to the Chapter 24-1. Names and Structures of Carbohydrates The naming system presented in this section comes from an assortment of historically derived common names organized into a semiofficial framework that is universally used. So, sugars are all ketones or aldehydes con￾taining alcohol groups, and their names all end in -ose. Almost all of them have stereocenters; and they are usually drawn in Fischer projections, with the carbon chain vertical and the carbonyl group nearest the top. If the stereocenter nearest the bottom of the Fischer projection has the OH on the right, it has an R configura￾tion, and the sugar is said to belong to the D family. If this OH is on the left, you have an S configuration and an L-sugar. Look at Figures 24-1 and 24-2. Each horizontal row contains structures that are all diastereomers of one another. None of the mirror-image structures (enantiomers) of any of these is illustrated; the mirror im￾age of any D-sugar is just an L-sugar with the same name. 423 1559T_ch24_423-438 10/20/05 4:54 AM Page 423